Wednesday, September 1, 2010

1/137.036

This is the alpha constant, a pure number which determines the structure of atoms in our universe. Had it been more than 4% different it would be impossible to have stable carbon atoms, and therefore there would not be carbon-based life-forms writing blogs and pondering about the mystery of this number.

To get the alpha constant you must multiply the square of the electron charge by 2 pi and then divide the product by the product of the speed of light times the Planck constant. So it is a constant of constants, with the difference that is dimensionless, i.e. id does not have measurement units. If an alien civilization used any other different set of measurement units to describe the same physical constants they would arrive at the same, pure, number.

So why this number? Why this universe so fine-tuned for life? During the long debate about the alpha constant some of the most logical, and at the same time crazy, hypotheses, were (a) that there are infinite number of universes and we just happen to inhabit in the life-friendly one – the “multiple universes hypotheses” and (b) that we inhabit a small part of a much, much, much bigger universe where all kinds of variations of nature’s constants occur – “the multiverse hypothesis”.

In a paper just submitted toPhysical Review Letters, a team led by John Webb and Julian King fromthe University of New South Walesin Australia present evidence that the fine-structure constant may not actually be constant after all; evidence in favour of a multiverse. If their observations stand the test of independent duplication, then we can imagine the multiverse as a giant ocean, lifeless for the most part, where nothing happens, and only after travelling for an endless distance the interuniversal explorer of our imagination may come along a tiny coral reef, mostly dead too but still too interesting not to miss.

For our explorer would observe structure and complexity therein, and if she looked deeper still, she would discover the strangest and most wonderful behaviour of matter and energy, how they bonded together to form carbon-based compounds, that became more complex still, they reproduced themselves, they developed into ecosystems, into life, and at some stage, given enough time and vast amounts of luck, into intelligence.